chuck thread size

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chuck thread size

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Viewing 14 posts - 1 through 14 (of 14 total)
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  • #187816
    mick70
    Participant
      @mick70

      picked up load of bits today from where i bought my southbend lathe.

      with stuff is a pratt bernard 4 jaw independent chuck now thread is lot smaller than stuff on southbend.

      anyone know what size thread is likely to be?

      havent got any bore gauges and thread starts fair way down hole.

      thanks

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      #17694
      mick70
      Participant
        @mick70
        #187817
        JasonB
        Moderator
          @jasonb

          #187818
          Ian P
          Participant
            @ianp
            Posted by JasonB on 26/04/2015 17:06:53:

            The piece I have is much longer

            #187819
            JohnF
            Participant
              @johnf59703

              Educated guess, if the thread is in the chuck body and not a backplate attached to the chuck it is quite likely to be a "Myford" thread. That is 1 1/8" x 12tpi Whit form.

              May of course be something completely different !

              #187821
              paul 1950
              Participant
                @paul1950

                if is the chuck with the built in thread its not worth much and if was mine i would bin it. bee caught out with chuck thread sizes before. sold a southbend chuck to someone with a boxford lathe and it came back. it screwed on nearly all the way but not all the way.

                #187827
                Bazyle
                Participant
                  @bazyle

                  Southbend lathe is UNC 60 degree while Boxfod is Whitworth 55 degree though tpi is the same.

                  A built in thread is good in many ways as it reduces overhang.

                  Cut a piece of thickish cardboard to a taper spanning the rough sixe of the hole. Screw it in and it will be marked up with the tread spacings at the core diameter of the thread. Make a few adjustments and you know the parameters. Do a bit of googling and you know what the chuck is off. You can also use bits of soft wood, like balsa bits of wood with plasticine on them, a few brain cells helps too.

                  Edited By Bazyle on 26/04/2015 18:45:10

                  #187828
                  JasonB
                  Moderator
                    @jasonb

                    If its in reasonable nick I would not be throwing it away, With second hand 4-jaws with threaded bodies fetching £100 thats worth finding out what the thread is. And if its a back plate one then with a new backplate it will fit your lathe.

                    Stick up a couple of photos showing teh ref number of teh chuck and what dia it is.

                     

                    J

                    Edited By JasonB on 26/04/2015 18:49:25

                    #187830
                    mick70
                    Participant
                      @mick70

                      the numbers on it are.

                      e12380

                      1548

                      and 16130

                      .

                      #187831
                      mick70
                      Participant
                        @mick70

                        would rather find size then try to make adaptor so i can use it.

                        #187832
                        mick70
                        Participant
                          @mick70

                          its a 6" dia.

                          threaded section is part of chuck no backplate.

                          #187834
                          Bazyle
                          Participant
                            @bazyle
                            Posted by naughtyboy on 26/04/2015 19:07:44:

                            would rather find size then try to make adaptor so i can use it.

                            That's the spirit yes

                            #187845
                            Clive Foster
                            Participant
                              @clivefoster55965

                              If its lots smaller than the Southbend size it could be 7/8 diameter by 9 or 12 TPI as used on small spindle Myford ML 1 to 4 series machines, related Drummonds and other makes. Threaded back 4 jaws of 6" diameter with relatively small mounting threads were not uncommon. I've had a couple or three through my hands over the years despite never having a machine they would fit! Second and third photos down on this **LINK** shows an example on a nicely re-furbed ML2.

                              Before you make an adapter it might be worth investigating to see if the body can be bored out to take the larger thread.

                              Clive

                              Edited By Clive Foster on 26/04/2015 21:00:01

                              #187847
                              Robbo
                              Participant
                                @robbo

                                Measure the plain part of the hole before the threads, you can reach that with a vernier/digital caliper.   Not the most accurate but near enough for now.

                                If it measures 1.24" – 1.25" that's the size for a Myford 7 series register.

                                Edited By Robbo on 26/04/2015 21:07:20

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